//  boost timer.hpp header file  ---------------------------------------------//
 
 //  Copyright Beman Dawes 1994-99.  Distributed under the Boost
 //  Software License, Version 1.0. (See accompanying file
 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
 //  See http://www.boost.org/libs/timer for documentation.
 
 //  Revision History
 //  01 Apr 01  Modified to use new <boost/limits.hpp> header. (JMaddock)
 //  12 Jan 01  Change to inline implementation to allow use without library
 //             builds. See docs for more rationale. (Beman Dawes) 
 //  25 Sep 99  elapsed_max() and elapsed_min() added (John Maddock)
 //  16 Jul 99  Second beta
 //   6 Jul 99  Initial boost version
 
 #ifndef BOOST_TIMER_HPP
 #define BOOST_TIMER_HPP
 
 #include <boost/config.hpp>
 #include <ctime>
 #include <boost/limits.hpp>
 
 # ifdef BOOST_NO_STDC_NAMESPACE
     namespace std { using ::clock_t; using ::clock; }
 # endif
 
 
 namespace boost {
 
 //  timer  -------------------------------------------------------------------//
 
 //  A timer object measures elapsed time.
 
 //  It is recommended that implementations measure wall clock rather than CPU
 //  time since the intended use is performance measurement on systems where
 //  total elapsed time is more important than just process or CPU time.
 
 //  Warnings: The maximum measurable elapsed time may well be only 596.5+ hours
 //  due to implementation limitations.  The accuracy of timings depends on the
 //  accuracy of timing information provided by the underlying platform, and
 //  this varies a great deal from platform to platform.
 
 class timer
 {
  public:
          timer() { _start_time = std::clock(); } // postcondition: elapsed()==0
 //         timer( const timer& src );      // post: elapsed()==src.elapsed()
 //        ~timer(){}
 //  timer& operator=( const timer& src );  // post: elapsed()==src.elapsed()
   void   restart() { _start_time = std::clock(); } // post: elapsed()==0
   double elapsed() const                  // return elapsed time in seconds
     { return  double(std::clock() - _start_time) / CLOCKS_PER_SEC; }
 
   double elapsed_max() const   // return estimated maximum value for elapsed()
   // Portability warning: elapsed_max() may return too high a value on systems
   // where std::clock_t overflows or resets at surprising values.
   {
     return (double((std::numeric_limits<std::clock_t>::max)())
        - double(_start_time)) / double(CLOCKS_PER_SEC); 
   }
 
   double elapsed_min() const            // return minimum value for elapsed()
    { return double(1)/double(CLOCKS_PER_SEC); }
 
  private:
   std::clock_t _start_time;
 }; // timer
 
 } // namespace boost
 
 #endif  // BOOST_TIMER_HPP